juliensimon/planck-cold-clumps

Planck Catalogue of Galactic Cold Clumps (PGCC)

Credit: NASA/DOE/Fermi LAT Collaboration

Part of the Astronomy Datasets collection on Hugging Face.

The Planck Catalogue of Galactic Cold Clumps (PGCC) — 13,242 cold, dense sources in the interstellar medium detected by the ESA Planck satellite at submillimeter wavelengths, sourced from VizieR.

Dataset description

Galactic cold clumps are cold, dense regions in the interstellar medium (ISM) with dust temperatures typically between 6 and 20 K, significantly colder than their surrounding environment. These compact structures represent the earliest stages of the star formation process — gravitationally bound or pre-gravitationally bound condensations that may eventually collapse to form protostars. Many are candidate pre-stellar cores, the seeds from which new stars and planetary systems will emerge.

The PGCC was compiled from the full Planck all-sky survey using a multi-frequency detection algorithm that identifies sources colder than their local background in the 857, 545, and 353 GHz (350, 550, and 850 micron) bands. Planck's all-sky coverage at submillimeter wavelengths makes it uniquely suited for this task — no other observatory has mapped the entire sky at these frequencies with comparable sensitivity. Ground-based submillimeter telescopes can observe only small patches of sky, and previous space missions (IRAS, Herschel) either lacked the spectral coverage or the all-sky field of view needed to build a complete census of Galactic cold dust sources.

Each PGCC entry includes flux densities at three Planck bands (and 3000 GHz / 100 micron where available), dust temperature and spectral emissivity index derived from modified blackbody fitting, H2 column density, angular size, and quality flags. The clumps span the full range of Galactic environments: from nearby molecular clouds (Taurus, Ophiuchus, Orion) at distances of 100-500 pc to distant complexes in the outer Galaxy beyond 5 kpc. Their dust temperatures, typically 5-8 K colder than the warm diffuse ISM (~18-20 K), identify them as sites where radiative shielding and high density allow efficient cooling.

The PGCC is a cornerstone resource for star formation studies, providing targets for high-resolution follow-up with ALMA, NOEMA, and JCMT to characterize their internal structure, kinematics, and fragmentation. It bridges the gap between the large-scale ISM structure traced by CO surveys and the individual protostellar cores revealed by interferometric observations.

Schema

Column	Type	Description
name	string	PGCC catalog designation (e.g. PGCC G000.00+00.00)
glon_deg	float64	Galactic longitude (degrees)
glat_deg	float64	Galactic latitude (degrees)
ra_deg	float64	Right ascension J2000 (degrees)
dec_deg	float64	Declination J2000 (degrees)
snr	float64	snr
snr_857ghz	float64	Signal-to-noise ratio at 857 GHz
snr_545ghz	float64	Signal-to-noise ratio at 545 GHz
snr_353ghz	float64	Signal-to-noise ratio at 353 GHz
maj	float64	maj
e_maj	float64	e_maj
min	float64	min
e_min	float64	e_min
position_angle_deg	float64	Position angle of the major axis (degrees, east of north)
e_pa	float64	e_pa
f3000c	float64	f3000c
e_f3000c	float64	e_f3000c
f857c	float64	f857c
e_f857c	float64	e_f857c
f545c	float64	f545c
e_f545c	float64	e_f545c
f353c	float64	f353c
e_f353c	float64	e_f353c
f3000w	float64	f3000w
e_f3000w	float64	e_f3000w
f857w	float64	f857w
e_f857w	float64	e_f857w
f545w	float64	f545w
e_f545w	float64	e_f545w
f353w	float64	f353w
e_f353w	float64	e_f353w
q_flux	int64	q_flux
fblend	int64	fblend
fblenddist	float64	fblenddist
fblendb857	float64	fblendb857
fblendb545	float64	fblendb545
fblendb353	float64	fblendb353
tempc	float64	tempc
e_tempc	float64	e_tempc
btempc	float64	btempc
betac	float64	betac
e_betac	float64	e_betac
bbetac	float64	bbetac
tempbeta2c	float64	tempbeta2c
e_tempbeta2c	float64	e_tempbeta2c
btempbeta2c	float64	btempbeta2c
tempw	float64	tempw
e_tempw	float64	e_tempw
btempw	float64	btempw
betaw	float64	betaw
e_betaw	float64	e_betaw
bbetaw	float64	bbetaw
tempbeta2w	float64	tempbeta2w
e_tempbeta2w	float64	e_tempbeta2w
btempbeta2w	float64	btempbeta2w
distoedr7	float64	distoedr7
e_distoedr7	float64	e_distoedr7
distne	float64	distne
e_distne	float64	e_distne
distmoc	float64	distmoc
e_distmoc	float64	e_distmoc
distopt	int64	distopt
q_dist	int64	q_dist
distance_pc	float64	Estimated distance (pc)
distance_err_pc	float64	Uncertainty on distance (pc)
mass	float64	mass
e_mass	float64	e_mass
b1mass	float64	b1mass
b2mass	float64	b2mass
b3mass	float64	b3mass
size	float64	size
e_size	float64	e_size
b1size	float64	b1size
b2size	float64	b2size
b3size	float64	b3size
dens	float64	dens
e_dens	float64	e_dens
b1dens	float64	b1dens
b2dens	float64	b2dens
b3dens	float64	b3dens
lum	float64	lum
column_density_cm2	float64	H2 column density (cm^-2)
column_density_err_cm2	float64	Uncertainty on H2 column density (cm^-2)
b1nh2	float64	b1nh2
b2nh2	float64	b2nh2
b3nh2	float64	b3nh2
nhotsrc	float64	nhotsrc
flmc	int64	flmc
fsmc	int64	fsmc
fecc	int64	fecc
fpccs857	int64	fpccs857
fpccs545	int64	fpccs545
fpccs353	int64	fpccs353
fpccs217	int64	fpccs217
fpccs143	int64	fpccs143
fpccs100	int64	fpccs100
fpccs70	int64	fpccs70
fpccs44	int64	fpccs44
fpccs30	int64	fpccs30
fpsz	int64	fpsz
fphz	int64	fphz
fhkpgcc	int64	fhkpgcc

Quick stats

• 13,242 cold clumps across the full Galactic sky
• 0 with measured dust temperature (median 0.0 K, range 0.0--0.0 K)
• 10,792 with H2 column density estimates
• 5,628 with distance estimates

Usage

from datasets import load_dataset

ds = load_dataset("juliensimon/planck-cold-clumps", split="train")
df = ds.to_pandas()

# Coldest clumps (potential pre-stellar cores)
coldest = df[df["temperature_k"] < 10].sort_values("temperature_k")
print(f"{len(coldest):,} clumps colder than 10 K")

# Clumps with high column density (dense cores)
if "column_density_cm2" in df.columns:
    dense = df[df["column_density_cm2"] > 1e22]
    print(f"{len(dense):,} dense clumps (N_H2 > 10^22 cm^-2)")

# Temperature distribution
import matplotlib.pyplot as plt
df["temperature_k"].dropna().hist(bins=50)
plt.xlabel("Dust Temperature (K)")
plt.ylabel("Count")
plt.title("PGCC Dust Temperature Distribution")

Data source

Planck Catalogue of Galactic Cold Clumps, published by the Planck Collaboration (Planck Collaboration XXVIII, 2016, A&A, 594, A28), accessed via VizieR, CDS Strasbourg.

Update schedule

Static dataset. The PGCC is based on the final Planck data release and is not expected to change.

Related datasets

• planck-sz2-clusters -- Planck SZ2 galaxy cluster catalog
• nebula-catalog -- Catalog of Galactic nebulae
• wise-hii-regions -- WISE Catalog of Galactic HII Regions
• gaia-dr3-young-stellar-objects -- Gaia DR3 young stellar objects

Pipeline

Source code: juliensimon/space-datasets

Support

If you find this dataset useful, please give it a ❤️ on the dataset page and share feedback in the Community tab! Also consider giving a ⭐️ to the space-datasets repo.

Citation

@dataset{planck_cold_clumps,
  author = {Simon, Julien},
  title = {Planck Catalogue of Galactic Cold Clumps (PGCC)},
  year = {2026},
  publisher = {Hugging Face},
  url = {https://huggingface.co/datasets/juliensimon/planck-cold-clumps},
  note = {Based on Planck Collaboration XXVIII (2016, A\&A, 594, A28) via VizieR CDS Strasbourg}
}

License

CC-BY-4.0